Dissertation

The urban planner´s role should be adapted to the current globalised and overspecialised economic and environmental context, envisioning a balance at the regional scale, apprehending not only new technologies, but also new mapping principles, that allow obtaining multidisciplinary integral overviews since the preliminary stages of the design process. The urban heat Island (UHI) is one of the main phenomena affecting the urban climate. In the Netherlands, during the heat wave of 2006, more than 1,000 extra deaths were registered. UHI-related parameters are an example of new elements that should be taken into consideration since the early phases of the design process.

Problem statement

Thus, the development of urban design guidelines to reduce the heat islands in Dutch cities and regions requires first an overall reflection on the heat island phenomenom (relevance of the large scale assessment, existing tools, instruments) and proposal of integrative and catalysing mapping strategies and then a specific assessment of the phenomenom at the selected locations in The Netherlands (testing those principles).

Main research question

Could the use of satellite imagery help analyse the UHI in the Netherlands and contribute to suggest catalysing mitigation acions actions implementable in the existing urban context of the cities, regions and provinces assessed?

Method

The development of urban design principles that aim at reaching a physical balance at the regional scale is critical to ensure a reduction of the UHI effect. Landsat and Modis satellite imagery can be analysed and processed using ATCOR 2/3, ENVI 4.7 and GIS, allowing not only a neighbourhood, city and regional scale assessment, but also generating holistic catalysing mapping typologies: game-board, rhizome, layering and drift, which are critical to ensure the integration of all parameters. The scientific inputs need to be combined not only with other disciplines but often also with existing urban plans. The connection between scientific research and existing agreed visions is critical to ensure the integration of new aspects into the plans.

Results

At the neighbourhood level the areas that have a greater heat concentration in the cities of Delft, Leiden, Gouda, Utrecht and Den Bosch are the city centres characterised by their red ceramic roof tiles, brick street paving, and canals. Several mitigation strategies could be implemented to improve the UHI effect in those areas; however, since the city centres are consolidated and listed urban areas, the mitigation measures that would be easier to implement would consist in improving the roof albedo. A consistent implementation of albedo improvement measures (improving the thermal behaviour not only of flat roofs, but also of tiled pitched roofs) of all roofs included in the identified hotspots (with an average storage heat flux greater than 90 W/m2) would help reduce the temperatures between 1.4°C and 3°C. Pre-war and post-war compact and ground-based neighbourhoods present similar thermal behaviour of the surface cover, and green neighbourhoods and small urban centres also present similar thermal behaviour.

At the city scale the analysis of 21 medium-size cities in the province of North Brabant, which belongs to the South region of the county -in relative terms the most affected by the UHI phenomenon during the heat wave of 2006-, reveals that albedo and normalised difference vegetation index (NDVI) are the most relevant parameters influencing the average nightime land surface temperature (LST). Thus, imperviousness, distance to the nearest town and the area of the cities do not seem to play a significant role in the LST night values for the medium-size cities analysed in the region of North Brabant, which do not exceed 7,700 ha in any case. The future growth of most medium-size cities of the regions will not per se aggravate the UHI phenomenon; in turn it will be the design of the new neighbourhoods that will impact the formation of urban heat in the province.

The average day LST of provincial parks in South Holland varies depending on the land use. The analysis of the average night LST varies depending of the land use of the patches. The following surfaces are arranged from the lowest to the highest temperatures: water surfaces, forests, cropland, and greenhouse areas. For each of these land uses, NDVI, imperviousness and landscape shape index (LSI) shape index influence the thermal behaviour of the patches differently. NDVI is inversely correlated to day LST for all categories, imperviousness is correlated to day LST for all areas which do not comprise a significant presence of greenhouses (grassland and built patches) and inversely correlated to LST for areas with a high presence of greenhouses (cropland and warehouses). Greenhouse surfaces have highly reflective roofs, which contribute to the reduction of day LST. Finally, landscape shape index varies depending on the nature of the surrounding patches, especially for small patches (built areas, forests and greenhouse areas). When the patches analysed are surrounded by warmer land uses, slender and scattered patches are warmer, more compact and large ones are cooler. In turn, when they are surrounded by cooler patches it is the opposite: slenderer and scattered patches are cooler and more compact and larger ones are warmer. In Midden-Delfland (1 of the 6 South Holland provincial parks), most of the hotspots surrounding the park are adjacent to grassland patches. The measure to increase the cooling capacity of those patches would consist in a change of land use and/or an increase of NDVI of the existing grassland patches.

Conclusions

Satellite imagery can be used not only to analyse the heat island phenomenom in Dutch neighbourhoods, cities and regions (identify neighbourhoods with highest surface temperature, identify impact of city size and morphology in surface temperature, calcuate average surface temperature for different land uses…), but also to suggest mitigation actions for the areas assessed. Moreover, satellite imagery is here used to generate catalysing mapping typologies: game-board, rhizome, layering and drift, ensuring that the measures proposed remain accurate enough to actualy be efficient and open enough to be compatible with the rest of urban planning priorities.

The urban planner´s role should be adapted to the current globalised and overspecialised economic and environmental context, envisioning a balance at the regional scale, apprehending not only new technologies, but also new mapping principles, that allow obtaining multidisciplinary integral overviews since the preliminary stages of the design process. The urban heat Island (UHI) is one of the main phenomena affecting the urban climate. In the Netherlands, during the heat wave of 2006, more than 1,000 extra deaths were registered. UHI-related parameters are an example of new elements that should be taken into consideration since the early phases of the design process.

Problem statement

Thus, the development of urban design guidelines to reduce the heat islands in Dutch cities and regions requires first an overall reflection on the heat island phenomenom (relevance of the large scale assessment, existing tools, instruments) and proposal of integrative and...

The urban planner´s role should be adapted to the current globalised and overspecialised economic and environmental context, envisioning a balance at the regional scale, apprehending not only new technologies, but also new mapping principles, that allow obtaining multidisciplinary integral...

Although there are many scientific peer-reviewed journal articles studying the Urban Heat Island effect in depth for different case study cities around the world from a climatological perspective, there seems to be a gap between the sophisticated available technologies (remote sensing), and the local UHI policies for the vast majority of medium-size to large cities. Urban planners punctually use images processed by remote sensing, but our discipline has not appropriated such a powerful tool yet.

The objective of this research is to explore the potential of the use of remote sensing technology for urban planners to be able to analyse the thermal behaviour of cities, in order to generate action plans for thermal master planning at the scales of the region and the city.

Although there are many scientific peer-reviewed journal articles studying the Urban Heat Island effect in depth for different case study cities around the world from a climatological perspective, there seems to be a gap between the sophisticated available technologies (remote sensing), and the local UHI policies for the vast majority of medium-size to large cities. Urban planners punctually use images processed by remote sensing, but our discipline has not appropriated such a powerful tool yet.

The objective of this research is to explore the potential of the use of remote sensing technology for urban planners to be able to analyse the thermal behaviour of cities, in order to generate action plans for thermal master planning at the scales of the region and the city.

Although there are many scientific peer-reviewed journal articles studying the Urban Heat Island effect in depth for different case study cities around the world from a climatological perspective, there seems to be a gap between the sophisticated available technologies (remote sensing), and...

In this study the satellite images were retrieved by Landsat 5TM and by Modis sensors; more specifically Modis 11A1, which provides specific layers with daytime and nighttime maps. Landsat 5TM is a moderate resolution satellite (with a resolution of 30 m for all its bands, except for band 6 which has a resolution of 120 m resampled to 30 m), and which has a temporal frequency of 16 days. Modis, in turn has a resolution of 1 km, and screens the surface of the earth on a daily basis. The main difference between the imagery retrieved by these two satellites is the resolution (Landsat is much better than Modis), and the fact that Modis provides night-time land surface temperature maps, whereas with Landsat 5TM only daytime land surface temperature imagery can be obtained. The parameters used as UHI indicators are: storage heat flux (calculated using daytime Landsat imagery), night-time land surface temperature (which have been retrieved through Modis) or daytime land surface temperature (retrieved through Landsat 5TM).

In the urban environment, storage heat flux maps were used for small surface analysis, such as in the article “The Urban Heat Island Effect in Dutch City Centers: Identifying relevant indicators and first explorations” (Echevarria Icaza et al., 2016c) where the average hotspot size analysed is 70.6 ha, in turn, Modis night-time imagery was used for the analysis of larger areas such as in the study “Surface thermal analysis of North Brabant cities and neighbourhoods during heat waves” (Echevarria Icaza et al., 2016b) where the average city size analysed is 1,565 ha. In the study “Using satellite imagery analysis to redesign provincial parks for a better cooling effect on cities. The case study of South Holland” (Echevarria Icaza et al., 2016a) Modis images were also used for the analysis of small land use patch surfaces, and as a matter of fact insignificant variations were found between the different land uses, and this is probably due to the coarse resolution compared to the patch size. Daytime land surface temperature (retrieved with Landsat 5TM) was used because the storage heat flux is not an UHI indicator for water patches and for non-urban patches due to the evapotranspiration effect.

The set of UHI parameters analysed varied depending on the purpose of the study. In all studies NDVI and albedo were mapped, and depending on the nature of the investigation other specific parameters were added.

In this study the satellite images were retrieved by Landsat 5TM and by Modis sensors; more specifically Modis 11A1, which provides specific layers with daytime and nighttime maps. Landsat 5TM is a moderate resolution satellite (with a resolution of 30 m for all its bands, except for band 6 which has a resolution of 120 m resampled to 30 m), and which has a temporal frequency of 16 days. Modis, in turn has a resolution of 1 km, and screens the surface of the earth on a daily basis. The main difference between the imagery retrieved by these two satellites is the resolution (Landsat is much better than Modis), and the fact that Modis provides night-time land surface temperature maps, whereas with Landsat 5TM only daytime land surface temperature imagery can be obtained. The parameters used as UHI indicators are: storage heat flux (calculated using daytime Landsat imagery), night-time land surface temperature (which have been retrieved through Modis) or daytime land surface...

In this study the satellite images were retrieved by Landsat 5TM and by Modis sensors; more specifically Modis 11A1, which provides specific layers with daytime and nighttime maps. Landsat 5TM is a moderate resolution satellite (with a resolution of 30 m for all its bands, except for band 6...

The impacts of climate changes to cities, which are home to over half of the world´s population, are already being felt. In many cases, the intensive speed with which urban centres have been growing means that little attention has been paid to the role played by climatic factors in maintaining the quality of life. Among the negative consequences of rapid city growth is the expansion of the problems posed by urban heat islands, defined as areas in a city that are much warmer than in other sites, especially in comparison with rural areas.

This paper analyses the consistency of the UHI related literature in three stages: first it outlines its characteristics and impacts in a wide variety of cities around the world, which poses pressures to public health in many different countries. Then it introduces strategies which may be employed in order to reduce its effects, and finally, it analyses available tools to systematize the initial high-level assessment of the phenomenon for multidisciplinary teams involved in the urban planning process. The analysis of the literature on the characteristics, impacts, strategies and digital tools to assess on the UHI, reveals the wide variety of parameters, methods, tools and strategies analysed and suggested in the different studies, which does not always allow to compare or standardize the diagnosis or solutions.

The impacts of climate changes to cities, which are home to over half of the world´s population, are already being felt. In many cases, the intensive speed with which urban centres have been growing means that little attention has been paid to the role played by climatic factors in maintaining the quality of life. Among the negative consequences of rapid city growth is the expansion of the problems posed by urban heat islands, defined as areas in a city that are much warmer than in other sites, especially in comparison with rural areas.

This paper analyses the consistency of the UHI related literature in three stages: first it outlines its characteristics and impacts in a wide variety of cities around the world, which poses pressures to public health in many different countries. Then it introduces strategies which may be employed in order to reduce its effects, and finally, it analyses available tools to systematize the initial high-level assessment of the phenomenon for...

The impacts of climate changes to cities, which are home to over half of the world´s population, are already being felt. In many cases, the intensive speed with which urban centres have been growing means that little attention has been paid to the role played by climatic factors in...

Scientists, climatologists, and urban planners have started to recognize the importance of nature at two very different scales: the global (metabolic) and the local (liveability) scales. The regional scale is the one at which these macro and micro approaches overlap. Future predictions foresee an increase of more than 2450 million urban inhabitants by 2050, thus new balanced urban visions need to be developed in order to guarantee the sustainability of urban areas. The Urban Heat Island (UHI) effect is a climate phenomenon resulting from unbalanced urban design arrangements. This paper analyses several design principles proposed by the 1920's regionalists from the UHI perspective. The preservation of the regional geographical landmarks, the implementation of urban containment policies (limiting city sizes), the increase of greenery and the development of green multifunctional blocks would help reduce the UHI in future urban developments.

Scientists, climatologists, and urban planners have started to recognize the importance of nature at two very different scales: the global (metabolic) and the local (liveability) scales. The regional scale is the one at which these macro and micro approaches overlap. Future predictions foresee an increase of more than 2450 million urban inhabitants by 2050, thus new balanced urban visions need to be developed in order to guarantee the sustainability of urban areas. The Urban Heat Island (UHI) effect is a climate phenomenon resulting from unbalanced urban design arrangements. This paper analyses several design principles proposed by the 1920's regionalists from the UHI perspective. The preservation of the regional geographical landmarks, the implementation of urban containment policies (limiting city sizes), the increase of greenery and the development of green multifunctional blocks would help reduce the UHI in future urban developments.

Scientists, climatologists, and urban planners have started to recognize the importance of nature at two very different scales: the global (metabolic) and the local (liveability) scales. The regional scale is the one at which these macro and micro approaches overlap. Future predictions foresee...

The world is increasingly concerned with sustainability issues. Climate change is not the least of these concerns. The complexity of these issues is such that data and information management form an important means of making the right decisions. Nowadays, however, the sheer quantity of data is overwhelming; large quantities of data demand means of representation that are comprehensible and effective. The above dilemma poses questions as to how one incorporates unknown climatologic parameters, such as urban heat, in future urban planning processes, and how one ensures the proposals are specific enough to actually adapt cities to climate change and flexible enough to ensure the proposed measures are combinable and compatible with other urban planning priorities.

Conventional urban planning processes and mapping strategies are not adapted to this new environmental, technological and social context. In order come up with more appropriate urban planning strategies, in its first section this paper analyses the role of the urban planner, reviews the wide variety of parameters that are starting to be integrated into the urban planners practice, and considers the parameters (mainly land surface temperature, albedo, vegetation and imperviousness) and tools needed for the assessment of the UHI (satellite imagery and GIS). The second part of the study analyses the potential of four catalysing mapping categories to integrate urban heat into spatial planning processes: drift, layering, game-board, and rhizome.

The world is increasingly concerned with sustainability issues. Climate change is not the least of these concerns. The complexity of these issues is such that data and information management form an important means of making the right decisions. Nowadays, however, the sheer quantity of data is overwhelming; large quantities of data demand means of representation that are comprehensible and effective. The above dilemma poses questions as to how one incorporates unknown climatologic parameters, such as urban heat, in future urban planning processes, and how one ensures the proposals are specific enough to actually adapt cities to climate change and flexible enough to ensure the proposed measures are combinable and compatible with other urban planning priorities.

Conventional urban planning processes and mapping strategies are not adapted to this new environmental, technological and social context. In order come up with more appropriate urban planning strategies, in its...

The world is increasingly concerned with sustainability issues. Climate change is not the least of these concerns. The complexity of these issues is such that data and information management form an important means of making the right decisions. Nowadays, however, the sheer quantity of data is...

In the Netherlands awareness regarding the Urban Heat Island (UHI) was raised relatively recently. Because of this recent understanding, there is a lack of consistent urban micro-meteorological measurements to allow a conventional UHI assessment of Dutch cities during heat waves. This paper argues that it is possible to retrieve relevant UHI information – including adaptation guidelines – from satellite imagery.

The paper comprises three parts. The first part consists of a study of suited indicators to identify urban heat islands from which a method is presented based on ground heat flux mapping. The second part proposes heat mitigation strategies and identifies the areas where these strategies could be applied within the hotspots identified in the cities of The Hague, Delft, Leiden, Gouda, Utrecht and Den Bosch. The third part estimates the reduction of urban heat generated by the increase of roof albedo in the hotspots of the six cities. The six cities hotspots are located within the boundaries of the 17th century city centres. In order to avoid interference with cultural values of these historical environments most likely UHI mitigation measures regard improving the thermal behaviour of the city roofs. For instance, applying white coatings on bitumen flat roofs (or replacing them by white single-ply membranes) and replacing sloped roof clay tiles by coloured tiles with cool pigments can reduce the urban heat hotspots by approximately 1.5°C.

Remote sensing provides high level information that provide urban planners and policy makers with overall design guidelines for the reduction of urban heat.

In the Netherlands awareness regarding the Urban Heat Island (UHI) was raised relatively recently. Because of this recent understanding, there is a lack of consistent urban micro-meteorological measurements to allow a conventional UHI assessment of Dutch cities during heat waves. This paper argues that it is possible to retrieve relevant UHI information – including adaptation guidelines – from satellite imagery.

The paper comprises three parts. The first part consists of a study of suited indicators to identify urban heat islands from which a method is presented based on ground heat flux mapping. The second part proposes heat mitigation strategies and identifies the areas where these strategies could be applied within the hotspots identified in the cities of The Hague, Delft, Leiden, Gouda, Utrecht and Den Bosch. The third part estimates the reduction of urban heat generated by the increase of roof albedo in the hotspots of the six cities. The six cities hotspots are...

In the Netherlands awareness regarding the Urban Heat Island (UHI) was raised relatively recently. Because of this recent understanding, there is a lack of consistent urban micro-meteorological measurements to allow a conventional UHI assessment of Dutch cities during heat waves. This paper...

The urban heat island effect is often associated with large metropolises. However, in the Netherlands even small cities will be affected by the phenomenon in the future (Hove et al., 2011), due to the dispersed or mosaic urbanisation patterns in particularly the southern part of the country: the province of North Brabant. This study analyses the average night-time land surface temperature (LST) of 21 North-Brabant urban areas through 22 satellite images retrieved by Modis 11A1 during the 2006 heat wave and uses Landsat 5 Thematic Mapper to map albedo and Normalised difference temperature index (NDVI) values. Albedo, NDVI and imperviousness are found to play the most relevant role in the increase of night-time LST. The surface cover cluster analysis of these three parameters reveals that the 12 “urban living environment” categories used in the region of North Brabant can actually be reduced to 7 categories, which simplifies the design guidelines to improve the surface thermal behaviour of the different neighbourhoods thus reducing the Urban Heat Island (UHI) effect in existing medium size cities and future developments adjacent to those cities.

The urban heat island effect is often associated with large metropolises. However, in the Netherlands even small cities will be affected by the phenomenon in the future (Hove et al., 2011), due to the dispersed or mosaic urbanisation patterns in particularly the southern part of the country: the province of North Brabant. This study analyses the average night-time land surface temperature (LST) of 21 North-Brabant urban areas through 22 satellite images retrieved by Modis 11A1 during the 2006 heat wave and uses Landsat 5 Thematic Mapper to map albedo and Normalised difference temperature index (NDVI) values. Albedo, NDVI and imperviousness are found to play the most relevant role in the increase of night-time LST. The surface cover cluster analysis of these three parameters reveals that the 12 “urban living environment” categories used in the region of North Brabant can actually be reduced to 7 categories, which simplifies the design guidelines to improve the surface thermal...

The urban heat island effect is often associated with large metropolises. However, in the Netherlands even small cities will be affected by the phenomenon in the future (Hove et al., 2011), due to the dispersed or mosaic urbanisation patterns in particularly the southern part of the country:...

The purpose of this research is to analyse the thermal behaviour of South Holland provincial parks during heat waves, in order to provide design adaptation guidelines to increase their cooling capacity over the hotspots present in their urban surroundings.

This research analyses the thermal behaviour of different land use patches (forests, cropland, grassland, water surfaces, built areas and greenhouse areas) present in the six South Holland provincial parks during heat waves. It studies their average night land surface temperature (LST) (with Modis 11A1), day LST (with Landsat 5TM), NDVI, imperviousness, patch size and patch shape index, and analyses through a multiple regression analysis the impact of each of these last four parameters in the night and day LST for each land use. Based on these conclusions, a set of design guidelines are provided to improve the cooling capacity of Midden-Delfland park areas which are adjacent to hotspots with day LST above 41°C and with day LST between 36°C and 41°C.

The average day LST within South Holland provincial parks varies from 25.9°C for water surfaces, to 31.4°C for forests, 33°C for cropland, 33.1°C for greenhouse areas, 34.9°C for grassland patches and 37.9°C for built areas. Within each land use category, NDVI, imperviousness and patch shape index influence differently the thermal behaviour of the patches. NDVI is inversely correlated to day LST for all categories, imperviousness is correlated to day LST for all areas which do not comprise a significant presence of greenhouses (grassland and built patches) and inversely correlated to LST for areas with a high presence of greenhouses (cropland and warehouses). Finally, the shape index varies depending on the nature of the surrounding patches, especially for small patches (built areas, forests and greenhouse areas).

Most of the hotspots surrounding the Midden-Delfland park are adjacent to grassland patches. The measure to increase the cooling capacity of those patches would consist in a change of land use and or an increase of the NDVI of the existing grassland patches. These suggestions to increase the cooling potential of the parks remain deliberately open in order to allow combining these measures with other spatial planning priorities.

The purpose of this research is to analyse the thermal behaviour of South Holland provincial parks during heat waves, in order to provide design adaptation guidelines to increase their cooling capacity over the hotspots present in their urban surroundings.

This research analyses the thermal behaviour of different land use patches (forests, cropland, grassland, water surfaces, built areas and greenhouse areas) present in the six South Holland provincial parks during heat waves. It studies their average night land surface temperature (LST) (with Modis 11A1), day LST (with Landsat 5TM), NDVI, imperviousness, patch size and patch shape index, and analyses through a multiple regression analysis the impact of each of these last four parameters in the night and day LST for each land use. Based on these conclusions, a set of design guidelines are provided to improve the cooling capacity of Midden-Delfland park areas which are adjacent to hotspots with day LST above 41°C and with...

The purpose of this research is to analyse the thermal behaviour of South Holland provincial parks during heat waves, in order to provide design adaptation guidelines to increase their cooling capacity over the hotspots present in their urban surroundings.

This thesis answers the overall question if the use of satellite imagery could help analysing the UHI in the Netherlands and suggests mitigation actions that can be implemented in the existing urban contexts of the cities, regions and provinces assessed. In order to answer this main research question a number of sub questions were formulated and studied from a theoretical perspective in part A: method. The investigation carried out in part A was used as a basis for the assessment of the urban heat in three specific case studies in the Netherlands in part B: results.

This thesis answers the overall question if the use of satellite imagery could help analysing the UHI in the Netherlands and suggests mitigation actions that can be implemented in the existing urban contexts of the cities, regions and provinces assessed. In order to answer this main research question a number of sub questions were formulated and studied from a theoretical perspective in part A: method. The investigation carried out in part A was used as a basis for the assessment of the urban heat in three specific case studies in the Netherlands in part B: results.

This thesis answers the overall question if the use of satellite imagery could help analysing the UHI in the Netherlands and suggests mitigation actions that can be implemented in the existing urban contexts of the cities, regions and provinces assessed. In order to answer this main research...